Patent GB-392615-A (GB)
Title: Improvements in carburetors
IPC: F02M19/08
Filed: 1931-11-21
Abstract: 392,615. Spray carburetters. FITZPATRICK, H. D., 94, Hope Street, Glasgow. - (Champion Carburetor Co. : 304, North Washington Street, Park Ridge, Illinois, U.S.A.) Nov. 21, 1931, No. 32312. [Class 7 (iii).] The carburetter has an air-inlet opening 26, Fig. 1, an outlet 27 controlled by a throttle valve 90, and a partition 30 having an opening 31 controlled by a suction-actuated valve 32. The partition has also an additional opening 36 to which is fitted a mixing tube 37, Figs. 1, 3, 11, and 12, having a base 38 provided with a peripheral recess 39 which communicates with the interior of the tube through openings 40. Air may enter the recess 39 through openings 41. A groove 42 is formed in the upper face of the base, and has drain holes 43 leading to a zone where the air can carry the drained fuel into tube 37. Openings 40, Fig. 12, connect the interior of tube 37 with the groove 39. The mixing tube can be adjusted in height by an eccentric pin 45, Fig. 3. The nozzle consists of a stationary member 50 having a base portion secured by a flange 53 and screws. A screw 55, Fig. 3, is reduced as at 56 to form an injector nozzle located in a recess 57 which communicates through a duct 58 with branches 59 which lead to the conical surface of the nozzle body. Fuel is supplied from the float chamber 62, Fig. 1, through a duct 61. Fitting over the nozzle body is a cap 69 secured by a screw 70 and spring 71 and having openings 72 adapted to register more or less with the branches 59. The openings 72 are located in air passages which meet at the base of the tube 37 which is tapered to conform with the top of the cap and into this tapered portion the drain holes 43 lead. The openings 72 are arranged outside the opening at the base of tube 37 and, by adjusting this tube vertically, the size of the air passages can be varied. The fuel is discharged across and not in the direction of the air flow. The bore 75 of the injector nozzle communicates through groove 76 and passages 77, 79 with a cylinder 80 containing an open-ended piston 82 loaded by a spring 84, the tensionof which can be adjusted by a screw 86. The space within the piston communicates through a duct 89 with the induction passage on the engine side of the throttle 90. This piston is kept raised by suction and fuel enters the space below it, but if the suction falls due to opening of the throttle, the piston is forced downwardly and fuel is ejected through the openings 72. One or more openings 93 and groove 94 serve to break the vacuum and prevent fuel being drawn past the piston. The cap 69 is rotated to vary the fuel supply by a rod 95, Fig. 1, connected to the air valve 32. The rod 95 passes loosely through a member 97, Figs. 1 and 9, which is pivotally mounted on a sleeve 103, Fig. 8, carried by a bar 105 secured to the spindle of the air valve. A spring 100, Fig. 9, serves to hold a nut 98 on rod 95 in contact with the member 97, the nut also serving to effect relative adjustment of the parts. The valve is loaded by a spring 35 which serves also to hold the cap 69 in fluidtight contact with the nozzle. Fluttering of valve 32 is prevented by a dashpot 109 which receives fuel from the float chamber, and a suction-actuated damper 126 is provided above the throttle 90 for the same purpose, the movements of the damper being steadied by a dashpot 129, Fig. 3, the piston-rod 132 passing through a plate 134. The air inlet 26 is closed by a manually actuated valve 120, having a hinged portion 123 adapted to be opened by suction at starting to prevent an excessive lowering of pressure. Fuel for idling is supplied through a passage 137, Fig. 4 (not shown), from the recess 39. In a modified construction, Fig. 13, showing a duplex carburetter, the outer portion 140 of the nozzle is fixed, and fuel control is effected by rotating inner valve members 146 by geared segments 150, 154 actuated by a rod 152 connected to the air valve. In a further modification, Fig. 16 (not shown), two nozzles are again employed and the caps, of the form shown in Fig. 1, are separately connected to the air valve 32. In a still further modification, Figs. 17, 19, 21, and 23, primary air enters at 177 and auxiliary air is admitted by a valve 159 controlled by a dashpot 161 and spring 162. The fuel nozzle body 147 is fixed, the inner part 146 being spring-loaded and adapted to be rotated from the throttle valve 90 through lever 178, 179 and adjustable cam bar 180 against which bears a roller 184 carried by an arm 182 of a lever mounted on an adjustable eccentric bearing, the end 185 of the other arm actuating a lever 172 on the fuel' valve stem. The valve member 146 has grooves 175 which terminate tangentially at 176, Fig. 21, in the upper conical part and conduct fuel to the discharge ports 142. Lugs 143, Fig. 23, are arranged on the part 147 and fit the throat of tube 166. The ports 142 are outside the air passages formed by these lugs, so that air rushing across these ports will blow the fuel into tube 166 instead of sucking it thereinto.